A developmental strategy will be applied to the behavioral, physiological, and neural analysis of early independent ingestion in rats. The proposed experiments make use of a species that undergoes a remarkable postnatal neural maturation and related behavioral ontogeny, each compressed into a time period that is practical to investigate. The use of developmental analysis provides unique opportunities to learn about the initial neurobehavioral organization of early appearing systems such as those for ingestion. The proposed research will: 1) define behavioral characteristics of the initiation, guidance, and maintenance of early independent ingestion and its related affective features; 2) investigate the ontogency of specific controls of ingestion and ingestion-related affect; 3) study the systems for gastric control of ingestion by taking advantage of simplifications provided by the immaturity of young pups; and 4) study the neural basis of early ingestion and its control using decerebrations and deoxyglucose autoradiographic techniques. An improved understanding of the origins of independent ingestion and its neural basis in rats may contribute to understanding ingestive processes in other species, and to insights about feeding and feeding pathologies in humans. Since ingestive behavior is one of the few complex appetitive behaviors present throughout life, these experiments also have a more general significance, that of providing a representative ontogenetic analysis of a "model" motivational system.